Many types of containment structures and systems have been developed, such as for controlling the interior environment of such an enclosed space. Environmental control may be desirable, for example, during the application or removal of material, coatings, and the like. In some cases, such application or removal methods are conducted to or from existing structures, such as building structures including interior spaces divided into rooms, hallways, stairs, and the like.
In creating a containment space, a volume is enclosed, and depending on characteristics of the materials involved (e.g. gas, liquid, particulate, etc.), the enclosed volume is effectively sealed from an outside environment. That way, the internal environment of the containment space can be controlled. Containment enclosures typically utilize a barrier material to effectively define the interior environment based upon existing structure (e.g. walls, ceiling, floor, doors, etc.), which barrier materials may also cover the various structural elements. That is not to say, however, that the barrier materials are utilized for masking purposes.
Masking of structural elements is typically done for other purposes, such as to prevent damage to or application of something to the covered components. A barrier material may also act as a mask as such structural elements would be covered by the barrier material; however, the goal is still to control the interior space environment. The barrier material actually creates a temporary and removable structure within such an existing structure.
In one current practice of removing harmful materials, such as asbestos, from a building, the surfaces of the room or hallway are covered with a plastic sheet. Any number of sheets can be used to enclose the desired space, which sheets need to be attached to the existing structure to effectively control the environment. The sheets are typically secured by spraying an adhesive as a primer, typically three to four inches wide, along the walls below the ceiling joint, attaching a plastic sheet to the adhesive primed wall using strips of duct tape over the plastic sheet and the adhesive, and finally securing the taped plastic sheet with staples or wooden strips nailed to the wall. The floor is also typically covered with two layers of plastic sheet with each sheet taped to the sides with duct tape.
Environmental control is based not only on creation of such a containment space, such as by the use of barrier materials, but also on the ability to maintain the enclosed space as desired for the relevant period of time. For asbestos removal, the environment must be strictly controlled during the entire abatement process. Any breach of the environment can have potentially negative consequences as particulate material may escape the controlled environment. According to many state codes governing asbestos removal procedures, breaches of such a controlled environment may need to be recorded and maintained.
According to the manner of creating an enclosed environment described above using plastic sheeting, adhesive applied along the sheet edges and taping techniques, one significant possibility for environment breach over time is the falling of one or more sheets from a wall or ceiling. The possibility of such occurring is exasperated because, for asbestos removal, environmental control also includes the maintenance of negative pressure within the enclosed environment. To do this, an exhaust structure is usually defined through a door opening or the like leading to the building space to be abated. An exhaust typically includes a fan sealingly connected to the barrier materials for drawing air from the space and leading to a filter system for removal of any airborne particles or the like. Controlled air into the space can also be provided to create the desired air flow and negative pressure.
However, such air flow and negative pressure can have a deleterious effect on the barrier materials, such a plastic sheeting. The sheeting tends to pull from the walls and billow from the wall, floor and ceiling surfaces away from the edges that are adhered to the walls, ceiling and floor. Billowing tends then to cause a peeling action of the sheeting from the surfaces, which peeling force acts against the cohesive force of the adhesive to the surfaces. Adhesives that are typically used for containment are usually chosen for the best holding power and are not usually chosen to be removable (meaning the sheets can be removed from the surfaces), so that damage often occurs, but the ability to remove is usually based upon the ability to peel the sheeting from the surfaces of the room. As such, a peeling action, such as caused by billowing, can cause a plastic sheet to fall from a wall, ceiling, or floor surface, which can further create a undesirable breach in the environmental control of a containment space.